Actually this 'll occur if u have large amount of statements to execute (in my case .javascript)

You have to make some adjustments in registry!

1. Using a Registry Editor such as Regedt32.exe,
open this key:HKEY_CURRENT_USER\Software\Microsoft\InternetE xplorer\Styles

Note If the Styles key is not present, create a new key that is called Styles.

2. Create a new DWORD value called "MaxScriptStatements" under this key
and set the value to the desired number of script statements.

By default the key doesn't exist. If the key has not been added,
Internet Explorer 4 defaults to 5,000,000 statements executed
as the trigger for the time-out dialog box.

Because the Internet Explorer 4.0, 5.0, 6, and 7 time-out is based on the number of
script statements executed, the time-out dialog box will not display during ActiveX control
or database-access delays. Endless loops in script will still be detected.

Even if I follow the steps in advanced tab in Tools menu,I get the popup.
I use the infragistics to find the value from a grid where in the value is not present.
I have handled a script where the text is not found.
But soon after the 'Text not found' popup,I am getting this weird popup namely
'Stop running this script?'.